This application claims the benefits of Korean Patent Application No. 2002-116, filed Jan. 2, 2002, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an apparatus for cleaning a print head of an ink jet printer, and more particularly, to a cleaning apparatus of a print head capable of maintaining a wiper to overlap the print head by a predetermined area.
2. Description of the Related Art
In general, an ink jet recording apparatus, such as an ink jet printer and an ink jet plotter, includes a carriage reciprocally moving on a main frame, on which an ink cartridge and a print head are mounted. The carriage is movably mounted on a guide shaft. The carriage is also connected to a timing belt that is fitted around a drive pulley coupled to a rotary shaft of a pulse motor. As the motor rotates, the carriage is moved in a main scanning direction relative to a recording sheet. A desired gap is provided between the print head and the recording sheet fed by a sheet-feeding roller. The print head ejects ink droplets upon receipt of drive pulses from a controller to print images on the recording sheet. Specifically, as the print head is reciprocally moved in the main scanning direction, the ink droplets are ejected through an ink spray nozzle of the print head to form the images on the recording sheet. In such an apparatus, an ink spraying operation is properly controlled in accordance with image information inputted from the controller of the ink jet recording apparatus.
With the construction described above, after a printing operation is performed, the ink remains at the ink spray nozzle. In a case that the printer is not used for a relatively longer period, the ink remaining at the ink spray nozzle is solidified. As the ink spray nozzle is partially or wholly clogged with the solidified ink, new ink droplets cannot be ejected in an appropriate amount, and as a result, a printing quality deteriorates.
In addition, the ink spray nozzle may be clogged with an extraneous substance such as dust, thereby exerting an adverse effect on the printing quality. Accordingly, in order to prevent the ink spray nozzle from being clogged, an apparatus for cleaning the print head is required.
FIG. 1 shows a perspective view of a conventional cleaning apparatus of a print head.
Referring to FIG. 1, the cleaning apparatus includes a housing 10 disposed under an ink cartridge 1, a plate 11 slidably moving in the housing 10, and a wiper 13 vertically mounted on an upper portion of the plate 11 by a holder (not shown). The wiper 13 is reciprocally moved by the plate 11 to clean the print head of the ink cartridge 1 positioned at a home (rest) location. Since it is a very important parameter as to how much the wiper 13 overlaps the print head, it is necessary to properly adjust a height of the wiper 13.
Meanwhile, the ink jet printer not only prints on the recording sheet of a standard size paper sheet like A4-sized sheets, but also prints on another recording sheet of a nonstandard size paper sheet like an envelope which is thicker than the standard size paper sheet. When an image is printed on the nonstandard size paper sheet which is relatively thicker, the head gap between the print head and the recording sheet is widened by a head gap adjusting mechanism to maintain the head gap of a predetermined distance.
Since a height of the wiper with respect to the recording sheet is fixed (constant), if the head gap is extended (adjusted), an overlapping area between the wiper and the printer head is reduced. As a result, the cleaning of the print head is not normally performed with the wiper having the reduced overlapping area with the print head, and an image quality deteriorates.
Accordingly, it is an object of the present invention to provide an apparatus for cleaning a print head of an ink jet printer that substantially obviates the above and other problems due to limitations and disadvantages of the related art
It is another object of the present invention to provide an apparatus for cleaning a print head having an improved structure that enables a wiper to overlap the print head by a predetermined area.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
According to an embodiment of the invention to solve the above and other objects, there is provided an apparatus for cleaning a print head disposed on a carriage an ink jet printer. The apparatus includes a movable plate reciprocally sliding under the carriage; a wiper, supported by the movable plate to clean the print head in a state that the wiper is overlapped with the print head by a predetermined height when the wiper is reciprocally moved, a pivot bar pivotally mounted to the movable plate and having one end supporting the wiper, and a driving unit adjusting the height of the wiper such that an overlapping amount of the wiper relative to the print head is constantly maintained by the pivot bar pivoting on the movable plate.
According to an aspect of the present invention, the driving unit includes a magnet member movably installed on the movable plate and having one end engaged with the pivot bar, and an electromagnet installed adjacent to the magnet member and disposed at a selected location relative to the magnet member to control the magnet member.
According to another aspect of the present invention, the electromagnet is a criss-cross of electromagnets having a south pole and a north pole being alternated with each other at a right angle, and the criss-cross electromagnets are selectively rotated at a desired angle around a center of the criss-cross electromagnets by a rotating motor.
The driving unit includes a solenoid installed on the movable plate to be cooperated with the another end of the pivot bar to control the pivot bar to move up and down with respect to the print head and pivot on the movable plate.
The apparatus further includes a wiper holder movably installed on the movable plate such that the wiper is lifted by the one end of the pivot bar in a state that the wiper is supported by the wiper holder.